Cutaneous anthrax is an infection of the skin caused by the bacterium Bacillus anthracis. The bacteria causes disease when it comes into contact with non-intact skin. During an infection, an initial skin lesion forms then blisters. The blister breaks down into a black ulcer and nearby lymph nodes may become infected and painful. A scar is often formed which then dries and falls off within two weeks. In 20% of untreated individuals, the infection may spread to the bloodstream and become fatal. Although with proper treatment, death is extremely rare.